Review 3

K

100

What are the units on K?

NO UNITS

200

Under what conditions are the numerical values of Kc and Kp equal?

deltan = 0

300

2H₂O(g) <--> 2H₂(g) + O₂(g)

Partial pressures are .04, .0045, and .003 atm respectively. Calculate Kp.

3.75x10^-5

400

Write the Kc expression for N₂(g) + 2O₂(g) <-->
N₂O₄(g)

Kc = [N2O4]/[N2][O2]²

500

At 500 C, Kp=1.45x10^-5 for N2(g) + 3H2 (g) <--> 2NH3 (g). What is Kc?

.0583

Manipulating K

100

How is the value of K affected by scaling up or down the coefficients of the reactants and products in the equation describing the reaction?

It's raised to that power

200

Kc = 120 for I2(g) + Br2(g) <--> IBr(g), What is Kc for the following rxn at the same temp?

1/2I₂(g) + 1/2Br₂ <--> IBr

11

300

NO(g) + NO3(g) <--> 2NO₂(g)

Write the K for the reverse reaction and say how they are related.

1/K

400

Kc=.11, what is the K when the reaction is multiplied by 2?

.0121

500

Calculate Kc for 2D <--> A + 2B

if A + 2B <--> C   K = 3.3

C <--> 2D K = .041

7.4

Q

100

How is an equilibrium constant different from a reaction quotient?

K is AT EQUILIBRIUM and Q can be anywhere

200

If Q = K

At equilibrium

300

If Q > K where does the reaction have to shift to reach equilibrium?

Shift to left (reactants)

400

If Q < K

Currently more reactants, so there will be a shift toward PRODUCTS

500

If Kc = 1.5x10^-3, N2(g) + O2(g) <--> 2NO(g) in which direction will the reaction proceed if the partial pressures of the three gases are all 1.00x10^-3 atm?

Left bc Q > K

Misc

100

Do you include solids/liquids in your K expression?

NOpe!

200

What does Le Chatelier's Principle state?

The reaction will return to equilibrium if disturbed (remember chairs ik that wasn't the best example though)

300

The value for DG⁰ for the rxn N2O(g) + 1/2O₂(g) <--> 2NO(g) is 68.9kJ. What is the value of K at 298K?

K = e^-DG/RT

I didn't work it out yet

400

What is the concentration of H₃O+ ions in .65M HNO3?

.65M

500

What is the square root of 10? NO CALCULATORS

3.16

Acid-base

100

Calculate the concentration of [OH-] in 4.5x10^-3M HCl

2.2x10^-12M

200

Degree of ionization if 4.07x10^-3M [H3O+] in an unknown acid .125M. Determine degree of ionization.

3.26%

300

The Ka of the conjugate acid of saccharin is 2.1x10^-11. What is the pKb?

3.32

400

Calculate pH of .00339M NaF at 25C.

7.35

500

What is the CB of H2O?

OH-